The Collaborative International Dictionary of English v.0.48:

Melodic \Me*lod"ic\, a. [L. melodicus, Gr. ?: cf. F.
   m['e]lodique.]
   Of the nature of melody; relating to, containing, or made up
   of, melody; melodious.
   [1913 Webster]

WordNet (r) 3.0 (2006):

melodic
    adj 1: containing or constituting or characterized by pleasing
           melody; "the melodious song of a meadowlark" [syn:
           melodious, melodic, musical] [ant: unmelodic,
           unmelodious, unmusical]
    2: of or relating to melody; "melodic harmony"

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "melodic":
   achingly sweet, agreeable, agreeable-sounding, appealing, ariose,
   arioso, canorous, cantabile, catchy, dulcet, euphonic, euphonious,
   euphonous, fine-toned, golden, golden-tongued, golden-voiced,
   honeyed, melic, mellifluent, mellifluous, mellisonant, mellow,
   melodious, music-flowing, music-like, musical, pleasant,
   pleasant-sounding, rich, silver-toned, silver-tongued,
   silver-voiced, silvery, singable, songful, songlike, sonorous,
   sweet, sweet-flowing, sweet-sounding, tunable, tuned, tuneful